Crude oil hydrorefining process



United States Patent Ofiice 3,252,895 Patented May 24, 1966 3,252,895CRUDE OIL HYDROREFINING PROCESS William K. T. Gleim, Island Lake, andJohn G. Gatsls, Des Plaines, Ill., assignors to Universal Oil ProductsCompany, Des Plaines, Ill., a corporation of Delaware No Drawing. FiledOct. 14, 1963, Ser. No. 316,117 10 Claims. (Cl. 208-264) The presentinvention relates to a method for preparing a novel catalystparticularly adaptable for utilization in the hydroreiining of petroleumcrude oils, heavy vacuurn gas oils, heavy cycle stocks, crudeoil-residuum, topped crude oils, etc. More specifically, the presentinvention is directed toward a process for hydrorefining petroleum crudeoil and other heavy hydrocarbon charge stocks to effect the removal ofnitrogen and sulfur therefrom, and affords unexpected advantages ineffecting the destructive removal of organo-metallic contaminants and/or the conversion of pentane-insoluble hydrocarbonaceous material.

Petroleum crude oil, and the heavier hydrocarbon fractions and/ordistillates obtained therefrom, particularly heavy vacuum gas oils andtopped crudes, generally contain nitrogenous and sulfurous compounds inlarge quantities. Inaddition, petroleum crude oils contain detrimentallyexcessive quantities of organo-metallic contaminants which exertdeleterious effects upon the catalyst utilized in various processes towhich the crude oil, topped crude oil, or heavy hydrocarbon fractionthereof may be ultimately subjected. The more common of such metalliccontaminants are nickel and vanadium, often existing in concentrationsin excess of about 50 p.p.m., although other metals including iron,copper, etc., may be present. These metals may exist within thepetroleum crude oil in a variety of forms: they may exist as metaloxides or as sulfides, introduced into the crude oil as a form ofmetallic scale; they may be present in the form of soluble salts of suchmetals; usually, however, they are present in the form oforgano-metallic compounds such as metal porphyrins and variousderivatives thereof. Although metallic contaminants, existing as oxideor sulfide scale, may be removed, at least in part, by a relativelysimple filtering technique, and the Water-soluble salts are at least inpart removable by washing and a subsequent dehydration procedure, a muchmore severe treatment is required to effect the destructive removal ofthe organo-metallic compounds, particularly to the degree which isnecessary to produce a crude oil or heavy hydrocarbon fraction suitablefor further processing.

In addition to organo-metallic contaminants, including metal porphyn'ns,crude oils contain greater quantities of sulfurous and nitrogenouscompounds than are generally found in lighter hydrocarbon fractions suchas gasoline, kerosene, light gas oil, etc. For example, a Wyoming sourcrude having a gravity of 23.2, API at 60 F., contains about 2.8% byweight of sulfur and approximately 2700 p.p.m. of total nitrogen,calculated as the elements thereof. Upon being subjected to a catalytichydrorefining process, the nitrogenous and sulfurous compounds areconverted into hydrocarbons, ammonia and hydrogen sulfide. However, thereduction in the concentration of the organo-metallic contaminants isnot easily achieved, and to the extent that the same no longer exert adetrimental effect with respect to further processing of the crude oil.Notwithstanding that the total concentration of these metalliccontaminants may be relatively'small, for example, less than about 10p.p.m. of metal porphyrins, calculated as the elemental metals,subsequent processing techniques will be adversely affected thereby.Thus, when a hydrocarbon charge stock containing metals in excess ofabout 3.0 p.p.m., is subjected to a cracking process for the purpose ofproducing lowerboiling components, metals become deposited upon thecatalyst employed, steadily increasing in quantity until such time asthe composition of the catalytic composite is changed to the extent thatundesirable results are obtained. That is to say, the composition of thecracking catalyst is closely controlled with respect to the nature ofthe charge stock being processed and to the desired product quality andquantity. This composition is changed considerably as-a result of thedeposition of the metallic contaminants thereupon, the changed compositeinherently resulting in changed catalytic characteristics. Such aneffect is undesirable since the deposition of metallic con taminantsupon the catalyst results in a lesser quantity of valuable liquidhydrocarbon product, and in large amounts of hydrogen and coke, thelatter also producing relatively rapid catalyst deactivation.

In addition to the foregoing described contaminating influences, crudeoils and other heavier hydrocarbon fractions contain excessivequantities of pentane-insoluble material. For example, the Wyoming sourcrude described above consists of about 8.3% by weight .ofpentane-insoluble asphaltenes; these are hydrocarbonaceous compoundsconsidered to be coke precursors having the tendency to becomeimmediately deposited within the reaction zone and onto the catalyticcomposite in the form of a high molecular weight, gummy residue. Sincethis constitutes a relatively large 'loss of charge stock, it iseconomically desirable to convert such asphaltenes into usefulhydrocarbon oil fractions, thereby increasing the liquid yield ofdesired product, based upon the quantity of oil charged to the process.

The object of the present invention is to provide a much more efficientprocess for hydrorefining heavier hydrocarbonaceous material, andparticularly petroleum crude oil, utilizing an unsupported catalystprepared in a particular manner. The term hydrorefining, as employedherein, connotes the catalytic treatment, in an atmosphere of hydrogen,of a hydrocarbon fraction or distillate for the purpose of eliminatingand/or reducing the concentration of the various contaminatinginfluences previously described. As hereinabove set forth, metals aregenerally removed from the charge stock by deposition of the same ontothe catalyst employed. This increases the amount of catalyst, activelyshields the catalytieally active surfaces and centers from the materialbeing processed, and thereby generally precludes the efiici entutilization of a fixed-bed catalyst system for processing suchcontaminated crude oil. Various moving-bed processes, employingcatalytically active metals deposited upon a carrier material consistingof silica and/or alumina, for example, or other refractory inorganicoxide material, are extremely erosive, causing plant maintenance tobecome difficult and expensive. The present invention teaches thepreparation of a colloidally dispersed, unsupported catalytic materialuseful in a slurry process, which catalytic material will not causeextensive erosion or corrosion of the reaction system. The presentprocess yields a liquid hydrocarbon product which is more suitable forfurther processing without experiencing the difficulties otherwiseresulting from the presence of. the foregoing contaminants. The processof the present invention is particularly advantageous for effecting theconversion of the organo-metallic contaminants without significantproduct yield loss, while simultaneously converting pentaneinsolublematerial into pentane-soluble liquid hydrocarbons.

The unsupported catalyst, utilized in the process of the presentinvention, is decomposed vanadyl acetylacetonate. We have previouslyfound that beta-diketone complexes selected from the metals of GroupVI-B of the Periodic Table (having an atomic number greater than 24).,molybdenum and tungsten, and the iron-group, when added to the petroleumcrude oil and decomposed there-- in, resulted in a totally unexpecteddegree of decontamination of the hydrocarbonaceous material. On theother hand, vanadyl acetylacetonate did not effect an acceptable degreeof decontamination of the crude oil, and the resulting hydrocarbonproduct efiluent necessarily required additional hydrorefining in orderto make the same suitable for further processing. We have now found thatsignificantly improved results are afforded, utilizing vanadylacetylacetonate, when the hydrorefining reactions are effected in thepresence of hydrogen sulfide which is added at the outset of theprocess, prior to initiating the hydrorefining reactions. As hereinafterindicated by specific example, notwithstanding that some hydrogensulfide may be formed during the process, an essential feature of thepresent invention is that a hydrogen sulfide be added prior to attainingthe level of operating conditions employed.

In addition to vanadyl acetylacetonate, other organovanadium compoundshave now been found to produce an acceptable degree of decontaminationof crude oils when utilized in the presence of added hydrogen sulfide.Such organovanadium compounds include vanadium xanthates, the vanadiumesters of various alcohols, the vanadium thioesters of variousrnercaptans, etc.

In a broad embodiment, therefore, the present invention relates to aprocess for hydrorefining a hydrocarbon charge stock which comprisesadmixing said charge stock with an organovanadium compound, and reactingthe resulting mixture with hydrogen in the presence of added hydrogensulfide.

In another broad embodiment, the present invention involves a processfor hydrorefining a hydrocarbon charge stock which process comprisesadmixing said charge stock with vanadyl acetylacetonate, and reactingthe resulting mixture with hydrogen in the presence of added hydrogensulfide.

A more limited embodiment of the present invention involves a processfor hydrorefining a hydrocarbon charge stock which comprises admixingsaid charge stock with vanadyl acetylacetonate, heating the resultingmixture at a temperature less than about 310 C. and for a timesufficient to decompose said vanadyl acetylacetonate, and reacting theresulting colloidal suspension with hydrogen and added hydrogen sulfide.

A specific embodiment of the present invention encompasses a process forhydrorefining a petroleum crude oil containing pentane-insolubleasphaltenes, which process comprises admixing said crude oil withvanadyl acetylacetonate, heating the resulting mixture at a temperaturebelow about 310 C. and for a time sufiicient to decompose said vanadylacetylactonate, reacting the resulting colloidal suspension withhydrogen and added hydrogen sulfide, at a temperature within the rangeof from about 225 C. to about 500 C. and at a pressure of from about 500to about 5000 pounds per square inch gauge, and recovering said crudeoil substantially free from pentaneinsoluble asphaltenes.

From the foregoing embodiments, it will be noted that the method of thepresent invention involves a preparation of a colloidal suspension ofthe catalytic material within the hydrocarbonaceous crude oil ultimatelysubjected to the hydrorefining reactions. Furthermore, the decompositionof the catalytic material, in this instance vanadyl acetylacetonate, iseffected below a temperature of about 310 C. to prevent prematurecracking of the petroleum crude oil, particularly in the absence ofhydrogen and added hydrogen sulfide. Briefly, the preferred method ofthe present invention involves dissolving vanadyl acetylacetonate in anappropriate solvent such as an alcohol, ketone or ester containing up toand including about carbon atoms per molecule. The solution is added topetroleum crude oil and the mixture heated at a temperature less thanabout 310 C. to remove the solvent and decompose the vanadylacetylacetonate, thereby creating a colloidally dispersed catalystsuspended within the pe- 4 troleum crude oil. The quantity of vanadylacetylacetonate is such that the colloidal suspension or dispersion,resulting when the material is decomposed, comprises from about 1.0% toabout 10.0% by weight, calculated, however, as elemental vanadium.

Typical of the alcohols suitable for use in preparing the solution ofvanadyl acetylacetonate, include isopropyl alcohol, isopentyl alcohol,methyl alcohol, amyl alcohol, mixtures thereof, etc. The resultingcolloidal dispersion is then passed into a suitable reaction zonemaintained at a temperature within the range of from about 225 C. toabout 500 C. and under a hydrogen pressure within the range of about 500to about 5000 pounds per square inch gauge. The process may be conductedas a batch type procedure or in an enclosed vessel through which thecolloidal suspension is passed; when effected in a continuous manner,the process may be conducted in either upward flow or downward flow. Thenormally liquid hydrocarbons are separated from the total reaction zoneeffluent by any suitable means, for example, through the use of acentrifuge or settling tanks, at least a portion of the resultingcatalyst-containing sludge being combined with the fresh petroleum crudeoil, and recycled to the reaction zone. In order to maintain the highestpossible degree of activity, it is preferred that at least a portion ofthe catalyst-containing sludge be removed from the process prior tocombining the remainder with fresh crude oil. The precise quantity ofcatalyst-containing sludge removed from the process will be dependentupon the desired degree of contaminant removal. It is further desirableto add a quantity of fresh vanadyl acetylacetonate to the petroleumcrude oil in order to compensate for that quantity of vanadium,calculated as the elemental metal, removed from the catalyst-containingsludge.

The colloidal dispersion of decomposed vanadyl acetylacetonate, or otherorganovanadium compound such as the vanadyl ester of isoamyl alcohol,the ester of t-butyl alcohol, etc., and crude oil is reacted withhydrogen under the operating conditions aforesaid, and in the presenceof added hydrogen sulfide. When dispersed within the crude oil, thevanadyl acetylacetonate, appears to be reduced to the extent of forminga crystalline structure as yet unidentified. As such, the catalyticmaterial is capable of hydrogenating, and/or hydrocracking, the moreeasily reduced sulfur compounds within the crude oil, thereby producinghydrogen sulfide. However, when the reactions are initiated in thepresence of added hydrogen sulfide, a more active form of catalyst isproduced immediately, which catalyst is capable of the destructiveremoval of the less easily reduced sulfur compounds. As hereinafterindicated by specific example, the more active form of catalyst is alsocapable of a greater degree of nitrogenous compound removal, yields ahydrorefined product effluent containing lesser quantities of metalliccontaminants and effects the conversion of a greater portion of thepentane-insoluble fraction. Since this more active form of catalystappears to have the same crystalline structure, also not as yetidentified, as the catalyst employed in the absence of added hydrogensulfide, the precise physical and/or chemical change effected therein isnot known with accuracy. The beneficial effects of the added hydrogensulfide appear to occur only when the latter is present at the time thehydrogenation reactions are being initiated. The hydrogen sulfide isadded to the hydrogen atmosphere in an amount of from about 1.0 to about15.0 mol percent.

The following examples are given to illustrate the present invention,and to indicate the effectiveness thereof in hydrorefining a petroleumcrude oil to remove various contaminating influences. It is not intendedto limit the present invention to the catalyst, concentrations ofmaterial, charge stock and/or conditions of operation utilized inpresenting these examples.

The crude oil employed was a Wyoming sour crude having a gravity of 23.2API at 60 F., containing about 2.8% by weight of sulfur, approximately2700 p.p.m. of nitrogen, 18 p.p.m. of nickel and 81 p.p.m. of vanadiumas metal porphyrins, computed as the elemental metals. In addition, thesour crude consisted of about 8.3% by weight of pentane-insolubleasphaltenes. As hereinafter indicated, the process of the presentinvention not only effects the conversion of a significant proportion ofthe pentane-insoluble asphaltenes, but also results in a substantialproduction of lower-boiling hydrocarbons as indicated by an increase ingravity, API at 60 F., of the normally liquid hydrocarbon portion of thetotal product efiluent.

Example I Vanadyl acetylacetonate in an amount of 21.0 grams, was addedto 100 grams of the Wyoming sour crude oil hereinabove described. Theresulting mixture was placed in an 850 cc. rocker-type autoclave,pressured to 100 atmospheres with hydrogen, and slowly heated to atemperature of 400' C., resulting in a pressure of 227 atmospheres;these conditions were maintained for a period of 8 hours. The autoclavewas allowed to cool, and was depressured; the normally liquidhydrocarbons indicated a gravity, API at 60 F., of 32.6. Analysesindicated that the liquidhydrocarbon fraction continued to becontaminated by 2180 p.p.m. of nitrogen, 1.86% by weight of sulfur,3.36% by weight of pentane-insoluble asphaltenes, 7.1 p.p.m. of nickeland 39.6 p.p.m. of vanadium, calculated as the elemental metals.

Vanadyl acetylacetonate in an amount of 42.0 grams was added to 250grams of the sour crude oil, accompanied by intimate mixing and heatingto a temperature of 250 C. for a period of 1 hour. A total of 100 gramsof the resulting mixture were placed in the 850 cc.-rocker typeautoclave, initially pressured to 100 atmospheres with hydrogen, andsubsequently heated to a temperature of 400 C., resulting in a pressureof 206 atmospheres. Aftera period of 4 hours, the normally liquidhydrocarbon portion of the product flluent indicated a gravity, API at60 F., of 25.0, and was contaminated by the continued presence of 2490p.p.m. of nitrogen, 1.68% by weight of sulfur, 3.7% by weight ofpentane-insoluble asphaltenes, 0.02 p.p.m. of nickel porphyrins and morethan 100 p.p.m. of vanadium porphyrins, calculated as the elementsthereof.

This example is given for the purpose of showing the inadequacy ofvanadyl acetylacetonate to function as a suitable hydrorefining catalystwhen admixed with the petroleum crude oil, and subjected tohydrorefining conditions in the absence of added hydrogen sulfide.Notwithstanding that there has been effected a partial cleanup of thecrude oil, the same is obviously not suitable for further processingwithout additional hydrorefining pretreatment. It should be noted that,notwithstanding the virtually complete elimination of nickel, there hasbeen an increase in the quantity of vanadium, indicating that at least aportion of the catalyst reacted to form additional contaminants.

Example 11 Vanadyl acetylacetonate, in an amount of 42.0 grams, wasadded to 500 grams of normal amyl alcohol, and heated over a steam bathto dissolve the vanadyl acetylacetonate. The solution was added to 250grams of this Wyoming sour crude, distilling off the amyl alcohol as thesame was added. Upon complete addition, the temperature was raised to180 C. for a period of 30 minutes, and 100 grams of the resultingmixture was placed in an autoclave and pressured to 100 atmospheres ofhydrogen. After a period of 8 hours at a temperature of 400 C. and aresulting final pressure of 205 atmospheres, the normally liquid portionof the product effluent indicated a gravity, API at 60 F. of 38.5, andwas contaminated by the presence of 942 p.p.m. of nitrogen, 0.40% byweight of sulfur, 0.64% by weight of pentane- 6 insoluble asphaltenes,0.1 p.p.m. of nickel and 63.0 p.p.m. of vanadium.

Sufiicient vanadyl acetylacetonate was added to grams of the Wyomingsour crude in alcohol solution, to result in a colloidal suspensioncontaining 2.90% by weight of vanadium. The mixture was intimatelyadmixed at a temperature of 250 C. for a period of 1 hour, and placed inthe rocker-type autoclave, initially pressured to 10 atmospheres withhydrogen sulfide then to 100 atmospheres with hydrogen. The autoclavewas heated to a temperature of 400 C., resulting in a pressure of 201atmospheres. After a period of 8 hours, the normally liquid portion ofthe total product efi luent, indicated a gravity, API at 60 F. of 37.5,contained 61 p.p.m. of nitrogen, 0.01% by weight of sulfur, less than0.03 p.p.m. of nickel and only 0.07 p.p.m. of vanadium, there being noindication of the continued presence of pentane-insoluble asphaltenes.

This example indicates the much improved results obtained when thevanadyl acetylacetonate is dispersed as an alcohol solution within thepetroleum crude oil, and hydrogen sulfide is added prior to initiatingthe hydrogenatting-hydrocracking reactions. The utilization of thevanadyl acetylacetonate has been shown to result in. a liquidhydrocarbon product suitable for further processing without theaccompanying detrimental effects otherwise resulting through thepresence of the various contaminating influences.

Example III The vanadyl ester of isoamyl alcohol, in an amount of 20.0grams, was added to 100 grams of the Wyoming sour crude oil, the mixturebeing heated at a temperature of about 250 C. to decompose the ester,thereby producing a colloidal suspension of 2.7% by weight of vanadiumwithin the crude oil. The colloidal dispersion was placed in the rockerautoclave and initially pressured to 10 atmospheres with hydrogensufide. Hydrogen was added to a pressure of 100 atmospheres, and thetemperature increased to 400 C., resulting in a pressure of 200atmospheres. The normally liquid portion of the product efiluent, after4 hours, indicated a gravity of 40.8 API at 60 F., and contained p.p.m.of nitrogen, 0.19% by weight of sulfur and 0.04% by weight ofpentane-insoluble asphaltenes.

Example I V The vanadyl ester of t-butyl alcohol, in an amount of 35.0grams was added to 200 grams of the crude oil. Without decomposition ofthe ester at a lower temperature, the mixture was placed in theautoclave under a pressure of 10 atmospheres of hydrogen sulfide and 90atmospheres of hydrogen. Upon heating to 400 C., the final pressure was203 atmospheres, which conditions were maintained for a period of 4hours. The normally liquid portion of the product efiluent indicated agravity of 296 API at 60 F., and contained 1960 p.p.m. of nitrogen,1.41% by weight of sulfur and 1.76% by weight of pentane-insolubleasphaltenes.

When the ester was decomposed prior to placing the mixture in theautoclave, under a pressure of 10 atmospheres of hydrogen sulfide and 90atmospheres of hydrogen, the liquid product efiluent indicated a gravityof 306 API, and contained 239 p.p.m. of nitrogen and 0.28% by weight ofsulfur, there being no indication of the continued presence ofpentane-insoluble asphaltenes.

This example is presented to show the improved results obtained when thecatalytic agent is decomposed within the charge stock, thereby forming acolloidal dispersion.

The foregoing specification and examples clearly indicate the benefitsafforded a process for hydrorefining heavy hydrocarbonaceous materialthrough the use of the present invention. The contaminating influenceshave been removed to the extent required for further processing withoutincurring the deleterious effects otherwise resultmg.

We claim as our invention:

1. A process for hydrorefining a hydrocarbon charge stock whichcomprises admixing said charge stock with an organovanadium compound,and reacting the resulting mixture with hydrogen and added hydrogensulfide at hydrorefining conditions, the hydrorefining reaction beinginitiated in the presence of the added hydrogen sulfide.

2. A process for hydrorefining a hydrocarbon charge stock whichcomprises admixing said charge stock with an organovanadium compounddecomposable at a temperature below about 310 C., heating the resultingmixture at a temperature below 310 C. for a time sufiicient to decomposesaid organovanadium compound, and reacting the resulting colloidaldispersion with hydrogen in the presence of added hydrogen sulfide, thehydrorefining reaction being initiated in the presence of the addedhydrogen sulfide.

3. The process of claim 2 further characterized in that saidorganovanadium compound comprises vanadyl acetylacetonate.

4. The process of claim 2 further characterized in that saidorganovanadium compound comprises the vanadyl ester of isoamyl alcohol.

5. The process of claim 2 further characterized in that saidorganovanadium compound comprises the vanadyl ester of t-butyl alcohol.

6. A process for hydrorefining a hydrocarbon charge stock whichcomprises admixing said charge stock with vanadyl acetylacetonate,heating the resulting mixture at a temperature less than about 310 C.and for a time sufficient to decompose said vanadyl acetylacetonate, andreacting the resulting colloidal suspension with hydrogen and addedhydrogen sulfide at a temperature above about 225 C. and at a pressuregreater than about 500 pounds per square inch gauge, the hydrorefiningreaction being initiated in the presence of the added hydrogen sulfide.

7. The process of claim 6 further characterized in that said colloidalsuspension is reacted with hydrogen and added hydrogen sulfide at atemperature within the range of from about 225 C. to about 500 C. andunder an imposed pressure of from about 500 to about 5000 pounds persquare inch gauge.

8. The process of claim 6 further characterized in that said colloidalsuspension comprises from about 1.0% to about 10.0% by weight ofdecomposed vanadyl acetylacetonate, calculated as elemental vanadium.

9. A process for hydrorefining a petroleum crude oil containingpentane-insoluble asphaltenes which comprises admixing said crude oilwith vanadyl acetylacetonate, heating the resulting mixture at atemperature less than about 310 C. and for a time sufficient todecompose said vanadyl acetylacetonate, reacting the resulting colloidalsuspension with hydrogen and added hydrogen sulfide at a temperatureabove about 225 C. and at a pressure greater than about 500 pounds persquare inch gauge, the hydrorefining reaction being initiated in thepresence of the added hydrogen sulfide, and recovering said crude oilsubstantially free from pentane-insoluble asphaltenes.

10. The process of claim 9 further characterized in that said hydrogensulfide is added in an amount within the range of from about 1.0 toabout 15.0 mol percent.

References Cited by the Examiner UNITED STATES PATENTS 3,165,463 1/1965Gleim et al. 208-264 DELBERT E. GANTZ, Primary Examiner.

S. P. JONES, Assistant Examiner.

1. A PROCESS FOR HYDROREFINING A HYDROCARBON CHARGE STOCK WHICHCOMPRISES ADMIXING SAID CHARGE STOCK WITH AN ORGANOVANADIUM COMPOUND,AND REACTING THE RESULTING MIXTURE WITH HYDROGEN AND ADDED HYDROGENSULFIDE AT HYDROREFINING CONDITIONS, THE HYDROREFINING REACTION BEINGINITIATED IN THE PRESENCE OF THE ADDED HYDROGEN SULFIDE.